Although Keeter had been a lifelong proponent of gun rights, witnessing Sunday’s horrific act of gun violence changed his mind. At least 58 people died and over 500 were injured at the Route 91 Harvest festival when Stephen Paddock, 64, fired on a crowd of 22,000 concertgoers from the 32nd floor of the Mandalay Bay hotel.

“I cannot express how wrong I was,” Keeter wrote in a note posted to Twitter on Monday. Although the band and its crew had access to firearms of their own, the guitarist said they were “useless” during the shooting, since they could have added to the confusion and terror at the scene.

Keeter said the feeling of reaching out to loved ones during the attack made him realize the issue of gun control “is completely and totally out of hand.”

“These rounds were powerful enough that my crew guys just standing in close proximity of a victim shot by this fucking coward received shrapnel wounds,” Keeter recalled.

The band began their performance on the festival’s main stage at 4 p.m. local time, around six hours before the shooting began during a performance by Jason Aldean on the same stage. Singers Luke Combs and Jake Owen had just taken a nearby stage when they heard gunfire, which created “chaos” that felt “like a movie,” Owentold the “Today” show.

Advocates for gun law reform began speaking out soon after the tragedy. Monday morning, Hillary Clintonslammed a bill in the House that would loosen U.S. gun control laws in a win for the NRA, if passed. Sen. Chris Murphy (D-Conn.), who became a vocal gun control advocate after the Sandy Hook Elementary attack in his home state, also issued a statement lambasting his colleagues in Congressfor being “so afraid of the gun industry that they pretend there aren’t public policy responses to this epidemic.”

“Our band and crew will never forget how that moment made them feel,” frontman Josh Abbott wrotein a tweetof his own.

Read Keeter’s full note below:

I’ve been a proponent of the 2nd amendment my entire life.

Until the events of last night. I cannot express how wrong I was. We actually have members of our crew with CHL licenses, and legal firearms on the bus.

They were useless.

We couldn’t touch them for fear police might think that we were part of the massacre and shoot us. A small group (or one man) laid waste to a city with dedicated, fearless police officers desperately trying to help, because of accss to an insane amount of fire power.

Enough is enough.

Writing my parents and the love of my life a goodbye last night and a living will because I felt like I wasn’t going to live through the night was enough for me to realize that this is completely and totally out of hand. These rounds were powerful enough that my crew guys just standing in close proximity of a victim shot by this fucking coward received shrapnel wounds.

We need gun control RIGHT. NOW.

My biggest regret is that I stubbornly didn’t realize it until my brothers on the road and myself were threatened by it.

We are unbelievably fortunate to not be among the number of victims killed or seriously wounded by this maniac.

A representative for the Josh Abbott Band declined HuffPost’s request for comment.